2.6.0 Alpha 5 has no application icon in the Linux appimage

[remcomeeder]

Description of the bug

I use PrusaSlicer-2.6.0-alpha5+linux-x64-GTK3-202303061441.AppImage and while for Alpha 3 and Alpha 4 I saw the app icon in the dock on Pop!OS with Alpha 5 there is no app icon anymore.

Project file & How to reproduce

Download PrusaSlicer-2.6.0-alpha5+linux-x64-GTK3-202303061441.AppImage and make it executable chmod a+x PrusaSlicer-2.6.0-alpha5+linux-x64-GTK3-202303061441.AppImage and start it using either the command line or file explorer.
Normally you see the app icon for the app but not for Alpha 5.

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

2.6.0 Alpha 5

Operating system

Pop!OS 22.04

Printer model

Prusa i3 mk3s+

[AndKe]

Devs, Please see arduino/arduino-ide#2190 on how to add the icon to the appimage.
This issue is also in 2.6.0